[BioC] Bioconductor

Robert Cribbie cribbie at criblab.yorku.ca
Wed Nov 12 20:13:50 MET 2003

I am a "newcomer" to the field of microarray analysis and I have run into
a snag trying to analyze some cdna data.

To determine if the same gene in two different groups is differentially
expressed I assume that I am comparing the expression levels of the two
groups after normalization. However, when I use bioconductor to normalize
the data (e.g., maNorm) I only end up with matrices of log ratios
(maM). How do I compare the expression levels of the two groups if I only
have the log ratios (and not the normalized expression levels).

Thanks for any help that you can provide.


                      Robert A. Cribbie

Assistant Professor		  Associate Coordinator
Department of Psychology	  Statistical Consulting Service
York University                   Institute for Social Research
Toronto, Ontario, Canada          York University
M3J 1P3

Phone: 416-736-5115 (x88615)      E-Mail: cribbie at yorku.ca
Fax: 416-736-5814                 Website: http://www.psych.yorku.ca/cribbie

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